title: Limnonectins: a new class of antimicrobial peptides from the skin secretion of the Fujian large-headed frog (Limnonectes fujianensis).
abstract: Amphibian skin secretions are rich sources of biologically-active peptides with antimicrobial peptides predominating in many species. Several studies involving molecular cloning of biosynthetic precursor-encoding cDNAs from skin or skin secretions have revealed that these exhibit highly-conserved domain architectures with an unusually high degree of conserved nucleotide and resultant amino acid sequences within the signal peptides. This high degree of nucleotide sequence conservation has permitted the design of primers complementary to such sites facilitating "shotgun" cloning of skin or skin secretion-derived cDNA libraries from hitherto unstudied species. Here we have used such an approach using a skin secretion-derived cDNA library from an unstudied species of Chinese frog - the Fujian large-headed frog, Limnonectes fujianensis - and have discovered two 16-mer peptides of novel primary structures, named limnonectin-1Fa (SFPFFPPGICKRLKRC) and limnonectin-1Fb (SFHVFPPWMCKSLKKC), that represent the prototypes of a new class of amphibian skin antimicrobial peptide. Unusually these limnonectins display activity only against a Gram-negative bacterium (MICs of 35 and 70 μM) and are devoid of haemolytic activity at concentrations up to 160 μM. Thus the "shotgun" cloning approach described can exploit the unusually high degree of nucleotide conservation in signal peptide-encoding domains of amphibian defensive skin secretion peptide precursor-encoding cDNAs to rapidly expedite the discovery of novel and functional defensive peptides in a manner that circumvents specimen sacrifice without compromising robustness of data.
authors.affiliation: Molecular Therapeutics Research, School of Pharmacy, Queen's University, Belfast BT9 7BL, Northern Ireland, UK.
authors.forename: Youjia
authors.initials: Y
authors.lastname: Wu
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Mei
authors.initials: M
authors.lastname: Zhou
authors.forename: Chengbang
authors.initials: C
authors.lastname: Ma
authors.forename: Xiaole
authors.initials: X
authors.lastname: Chen
authors.forename: Bing
authors.initials: B
authors.lastname: Bai
authors.forename: Tianbao
authors.initials: T
authors.lastname: Chen
authors.forename: Chris
authors.initials: C
authors.lastname: Shaw
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D001483:Base Sequence; D002176:Candida albicans / Q000187:drug effects; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000187:drug effects; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011898:Ranidae; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D023181:Antimicrobial Cationic Peptides